In many food preparation facilities, such as commercial kitchens and restaurants, the sink is a major tool used for disposing of various types of food waste. In some cases liquid food wastes, such as FOG are poured down the sink, and in other cases a mechanical chopper such as a garborator is used to shred the food waste as it leaves the sink and enters the wastewater system. Many food preparation establishments, such as commercial restaurants and the like, have multiple sinks for such food waste disposal.
In many jurisdictions, the disposal from commercial kitchens of FOG and FOG laden debris into the sanitary sewage system is prohibited. There are a number of reasons why this is so, including the ability of those types of materials to clog or plug sanitary sewage systems and the difficulty of adequately treating such materials in a sewage treatment facility. Therefore, many jurisdictions require that these materials be removed from the wastewater stream before permitting the wastewater stream to be added to the sanitary sewer system.
As a result, devices known as grease interceptors have been developed. These grease interceptors are connected to the wastewater effluent stream from the food preparation kitchen or other facility and are located before the sanitary sewer, typically within the kitchen. The grease interceptors may take a number of forms, but typically consist of an in-line container which is mounted at or below grade within the wastewater discharge system downstream of all of the sinks and the like. The container includes features that are configured to allow fats, oils and grease to float to the surface of the container where they can be skimmed off and physically removed for controlled disposal. In this way these wastes are removed from the wastewater before the wastewater enters the sanitary sewer system. Some examples of prior art grease interceptors include the following:
Canadian Patent No. 2,299,134 issued Sep. 1, 2009;
Canadian Patent Application No. 2,672,865 filed Feb. 23, 2000;
U.S. Pat. No. 2,272,912, issued Feb. 10, 1942;
U.S. Pat. No. 2,102,430 issued Dec. 14, 1937;
U.S. Pat. No. 4,940,539 issued Jul. 10, 1990;
U.S. Pat. No. 5,431,826 issued Jul. 11, 1995;
U.S. Pat. No. 7,011,752 issued Mar. 14, 2006;
U.S. Pat. No. 7,300,588 issued Nov. 27, 2007; and
U.S. Pat. No. 8,007,016 issued Aug. 20, 2011.
While these different inventions all have various features and benefits, a consistent problem is efficiently separating FOG from wastewater. Deflector plates have been used to attempt to increase separation of grease, but the deflectors may not create sufficient separation of FOG from wastewater. Moreover, deflector plates which are fixed to the grease interceptor surface may be difficult to clean. Attempts to increase separation of FOG by radically modifying the flow of wastewater may have the undesirable effect of creating turbulent flow, which can erode trapped grease from the surface and cause FOG to enter the sanitary sewer system. What is desired is a way to control the flow of fluid through a grease interceptor to effectively separate FOG from wastewater without excessively turbulent flow. What is also desired is a way to provide for the separation of FOG using a grease interceptor which can be cleaned more easily.